text: /*
   * $Id: bitops.h,v 1.1.1.1 2001/02/22 14:58:58 serg Exp $
   * bitops.h: Bit string operations on the ppc
   */
  
  #ifdef __KERNEL__
  #ifndef _PPC_BITOPS_H
  #define _PPC_BITOPS_H
  
  #include <linux/config.h>
  #include <asm/byteorder.h>
  
  /*
   * The test_and_*_bit operations are taken to imply a memory barrier
   * on SMP systems.
   */
  #ifdef CONFIG_SMP
  #define SMP_WMB		"eieio\n"
  #define SMP_MB		"\nsync"
  #else
  #define SMP_WMB
  #define SMP_MB
  #endif /* CONFIG_SMP */
  
  #define __INLINE_BITOPS	1
  
  #if __INLINE_BITOPS
  /*
   * These used to be if'd out here because using : "cc" as a constraint
   * resulted in errors from egcs.  Things may be OK with gcc-2.95.
   */
  static __inline__ void set_bit(int nr, volatile void * addr)
  {
  	unsigned long old;
  	unsigned long mask = 1 << (nr & 0x1f);
  	unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  	
  	__asm__ __volatile__("\
  1:	lwarx	%0,0,%3
  	or	%0,%0,%2
  	stwcx.	%0,0,%3
  	bne-	1b"
  	: "=&r" (old), "=m" (*p)
  	: "r" (mask), "r" (p), "m" (*p)
  	: "cc" );
  }
  
  /*
   * non-atomic version
   */
  static __inline__ void __set_bit(int nr, volatile void *addr)
  {
  	unsigned long mask = 1 << (nr & 0x1f);
  	unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  
  	*p |= mask;
  }
  
  /*
   * clear_bit doesn't imply a memory barrier
   */
  #define smp_mb__before_clear_bit()	smp_mb()
  #define smp_mb__after_clear_bit()	smp_mb()
  
  static __inline__ void clear_bit(int nr, volatile void *addr)
  {
  	unsigned long old;
  	unsigned long mask = 1 << (nr & 0x1f);
  	unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  
  	__asm__ __volatile__("\
  1:	lwarx	%0,0,%3
  	andc	%0,%0,%2
  	stwcx.	%0,0,%3
  	bne-	1b"
  	: "=&r" (old), "=m" (*p)
  	: "r" (mask), "r" (p), "m" (*p)
  	: "cc");
  }
  
  static __inline__ void change_bit(int nr, volatile void *addr)
  {
  	unsigned long old;
  	unsigned long mask = 1 << (nr & 0x1f);
  	unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  
  	__asm__ __volatile__("\
  1:	lwarx	%0,0,%3
  	xor	%0,%0,%2
  	stwcx.	%0,0,%3
  	bne-	1b"
  	: "=&r" (old), "=m" (*p)
  	: "r" (mask), "r" (p), "m" (*p)
  	: "cc");
  }
  
  /*
   * test_and_*_bit do imply a memory barrier (?)
   */
  static __inline__ int test_and_set_bit(int nr, volatile void *addr)
  {
  	unsigned int old, t;
  	unsigned int mask = 1 << (nr & 0x1f);
  	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
  
  	__asm__ __volatile__(SMP_WMB "\
  1:	lwarx	%0,0,%4
  	or	%1,%0,%3
  	stwcx.	%1,0,%4
  	bne	1b"
  	SMP_MB
  	: "=&r" (old), "=&r" (t), "=m" (*p)
  	: "r" (mask), "r" (p), "m" (*p)
  	: "cc", "memory");
  
  	return (old & mask) != 0;
  }
  
  /*
   * non-atomic version
   */
  static __inline__ int __test_and_set_bit(int nr, volatile void *addr)
  {
  	unsigned long mask = 1 << (nr & 0x1f);
  	unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  	unsigned long old = *p;
  
  	*p = old | mask;
  	return (old & mask) != 0;
  }
  
  static __inline__ int test_and_clear_bit(int nr, volatile void *addr)
  {
  	unsigned int old, t;
  	unsigned int mask = 1 << (nr & 0x1f);
  	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
  
  	__asm__ __volatile__(SMP_WMB "\
  1:	lwarx	%0,0,%4
  	andc	%1,%0,%3
  	stwcx.	%1,0,%4
  	bne	1b"
  	SMP_MB
  	: "=&r" (old), "=&r" (t), "=m" (*p)
  	: "r" (mask), "r" (p), "m" (*p)
  	: "cc", "memory");
  
  	return (old & mask) != 0;
  }
  
  /*
   * non-atomic version
   */
  static __inline__ int __test_and_clear_bit(int nr, volatile void *addr)
  {
  	unsigned long mask = 1 << (nr & 0x1f);
  	unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  	unsigned long old = *p;
  
  	*p = old & ~mask;
  	return (old & mask) != 0;
  }
  
  static __inline__ int test_and_change_bit(int nr, volatile void *addr)
  {
  	unsigned int old, t;
  	unsigned int mask = 1 << (nr & 0x1f);
  	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
  
  	__asm__ __volatile__(SMP_WMB "\
  1:	lwarx	%0,0,%4
  	xor	%1,%0,%3
  	stwcx.	%1,0,%4
  	bne	1b"
  	SMP_MB
  	: "=&r" (old), "=&r" (t), "=m" (*p)
  	: "r" (mask), "r" (p), "m" (*p)
  	: "cc", "memory");
  
  	return (old & mask) != 0;
  }
  #else /* __INLINE_BITOPS */
  
  extern void set_bit(int nr, volatile void *addr);
  extern void clear_bit(int nr, volatile void *addr);
  extern void change_bit(int nr, volatile void *addr);
  extern int test_and_set_bit(int nr, volatile void *addr);
  extern int test_and_clear_bit(int nr, volatile void *addr);
  extern int test_and_change_bit(int nr, volatile void *addr);
  
  #endif /* __INLINE_BITOPS */
  
  static __inline__ int test_bit(int nr, __const__ volatile void *addr)
  {
  	__const__ unsigned int *p = (__const__ unsigned int *) addr;
  
  	return ((p[nr >> 5] >> (nr & 0x1f)) & 1) != 0;
  }
  
  /* Return the bit position of the most significant 1 bit in a word */
  static __inline__ int __ilog2(unsigned int x)
  {
  	int lz;
  
  	asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
  	return 31 - lz;
  }
  
  static __inline__ int ffz(unsigned int x)
  {
  	if ((x = ~x) == 0)
  		return 32;
  	return __ilog2(x & -x);
  }
  
  #ifdef __KERNEL__
  
  /*
   * ffs: find first bit set. This is defined the same way as
   * the libc and compiler builtin ffs routines, therefore
   * differs in spirit from the above ffz (man ffs).
   */
  static __inline__ int ffs(int x)
  {
  	return __ilog2(x & -x) + 1;
  }
  
  /*
   * hweightN: returns the hamming weight (i.e. the number
   * of bits set) of a N-bit word
   */
  
  #define hweight32(x) generic_hweight32(x)
  #define hweight16(x) generic_hweight16(x)
  #define hweight8(x) generic_hweight8(x)
  
  #endif /* __KERNEL__ */
  
  /*
   * This implementation of find_{first,next}_zero_bit was stolen from
   * Linus' asm-alpha/bitops.h.
   */
  #define find_first_zero_bit(addr, size) \
  	find_next_zero_bit((addr), (size), 0)
  
  static __inline__ unsigned long find_next_zero_bit(void * addr,
  	unsigned long size, unsigned long offset)
  {
  	unsigned int * p = ((unsigned int *) addr) + (offset >> 5);
  	unsigned int result = offset & ~31UL;
  	unsigned int tmp;
  
  	if (offset >= size)
  		return size;
  	size -= result;
  	offset &= 31UL;
  	if (offset) {
  		tmp = *p++;
  		tmp |= ~0UL >> (32-offset);
  		if (size < 32)
  			goto found_first;
  		if (tmp != ~0U)
  			goto found_middle;
  		size -= 32;
  		result += 32;
  	}
  	while (size >= 32) {
  		if ((tmp = *p++) != ~0U)
  			goto found_middle;
  		result += 32;
  		size -= 32;
  	}
  	if (!size)
  		return result;
  	tmp = *p;
  found_first:
  	tmp |= ~0UL << size;
  	if (tmp == ~0UL)        /* Are any bits zero? */
  		return result + size; /* Nope. */
  found_middle:
  	return result + ffz(tmp);
  }
  
  
  #define _EXT2_HAVE_ASM_BITOPS_
  
  #ifdef __KERNEL__
  
  #define ext2_set_bit(nr, addr)		__test_and_set_bit((nr) ^ 0x18, addr)
  #define ext2_clear_bit(nr, addr)	__test_and_clear_bit((nr) ^ 0x18, addr)
  
  static __inline__ int ext2_test_bit(int nr, __const__ void * addr)
  {
  	__const__ unsigned char	*ADDR = (__const__ unsigned char *) addr;
  
  	return (ADDR[nr >> 3] >> (nr & 7)) & 1;
  }
  
  /*
   * This implementation of ext2_find_{first,next}_zero_bit was stolen from
   * Linus' asm-alpha/bitops.h and modified for a big-endian machine.
   */
  
  #define ext2_find_first_zero_bit(addr, size) \
          ext2_find_next_zero_bit((addr), (size), 0)
  
  static __inline__ unsigned long ext2_find_next_zero_bit(void *addr,
  	unsigned long size, unsigned long offset)
  {
  	unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
  	unsigned int result = offset & ~31UL;
  	unsigned int tmp;
  
  	if (offset >= size)
  		return size;
  	size -= result;
  	offset &= 31UL;
  	if (offset) {
  		tmp = cpu_to_le32p(p++);
  		tmp |= ~0UL >> (32-offset);
  		if (size < 32)
  			goto found_first;
  		if (tmp != ~0U)
  			goto found_middle;
  		size -= 32;
  		result += 32;
  	}
  	while (size >= 32) {
  		if ((tmp = cpu_to_le32p(p++)) != ~0U)
  			goto found_middle;
  		result += 32;
  		size -= 32;
  	}
  	if (!size)
  		return result;
  	tmp = cpu_to_le32p(p);
  found_first:
  	tmp |= ~0U << size;
  	if (tmp == ~0UL)        /* Are any bits zero? */
  		return result + size; /* Nope. */
  found_middle:
  	return result + ffz(tmp);
  }
  
  /* Bitmap functions for the minix filesystem.  */
  #define minix_test_and_set_bit(nr,addr) ext2_set_bit(nr,addr)
  #define minix_set_bit(nr,addr) ((void)ext2_set_bit(nr,addr))
  #define minix_test_and_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
  #define minix_test_bit(nr,addr) ext2_test_bit(nr,addr)
  #define minix_find_first_zero_bit(addr,size) ext2_find_first_zero_bit(addr,size)
  
  #endif	/* __KERNEL__ */
  
  #endif /* _PPC_BITOPS_H */
  #endif /* __KERNEL__ */
  